weikengchen / anemoi-hash

Anemoi: a Family of ZK-friendly Arithmetization Oriented Hash Functions

Anemoi: a Family of ZK-friendly AO Hash Functions

This repository contains a first implementation in sage of the Anemoi family of hash functions. Anemoi is a family of Arithmetization Oriented Hash Functions that operates over prime and binary fields.

Our paper on Anemoi can be found on ePrint: https://eprint.iacr.org/2022/840.

Contents

The sage script anemoi.sage contains various routines to evaluate Anemoi (including AnemoiJive and AnemoiSponge) but also to generate the corresponding systems of equations.

First some basics functions allow to provide well-chosen parameters: field, number of rounds, linear layer, ... for various instances of Anemoi.

The class AnemoiPermutation then contains different sections:

• Sub-components: evaluate_sbox and linear_layer respectively apply our Flystel construction and the linear layer.
• Evaluation: eval_with_intermediate_values performs an evaluation of Anemoi using the SPN construction. The function also return intermediate values as this can be used to check the solutions of the systems of equations generated.
• Writing full system of equations: get_polynomial_variables, verification_polynomials and print_verification_polynomials allow to generate the corresponding multivariate system of polynomial equations. This indeed allowed us to perform our security analysis using Grobner basis attacks.

The two functions jive and sponge_hash are routines to evaluate AnemoiJive and AnemoiSponge that respectively correspond to our Merkle Compression function, and our Hash function.

Authors

• Clémence Bouvier, Sorbonne University, France - Inria, France
• Pierre Briaud, Sorbonne University, France - Inria, France
• Pyrros Chaidos, National & Kapodistrian University of Athens, Greece,
• Léo Perrin, Inria, France
• Vesselin Velichkov, University of Edinburgh, Scotland - Clearmatics, England

Third-party implementations

Please contact us if you have any Anemoi implementations to share.

License

This repository is distributed under the terms of the MIT License.